JPS5916914A - Cooling construction of furnace wall of blast furnace constituted of two layers cooling zone - Google Patents

Abstract

PURPOSE:To regulate the falling down and chemical erosion of refractory and to achieve the safety long life of furnace wall, by combining the stave-cooling system on the outside of furnace side into the lateral rectangular cooling board connection system. CONSTITUTION:A cooling board 11 is made from cast iron, etc., of which the inside is, in a casting manner, arranged with a cooling tube 12, situated at almost central part of furnace wall thickness, each cooling board being surrounded in circumferential direction of furnace body by lateral connection, and such ring shape boards 11 are, by a suitable interval, arranged in direction of height. Longitudinal row cooling staves 16 are, by a suitable interval, arranged in circumferential direction of furnace body near peripheral shell 17 of this cooling zone on the inside of furnace side and they construct the cooling zone on the outside of furnace side. This two layers cooling zone is constructed by working unshaped refractories 14, etc. in surroundings of the stave 16 and board 11 fixed to the shelf 17. Thus, the refractory 14 is wholly cooled and strongly held with the board 11, and its falling down can be protected by reducing its wearing. Even though the board 11 is exposed after several years operation, the cooling zone on shelf side is in a good condition and the shell is not heated at a high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling structure for the furnace body of a blast furnace, especially the furnace wall such as the furnace chest, the furnace belly, and the morning glory.゛As is well known, the furnace body is cooled to protect the refractory lining and steel shell of the blast furnace body from high temperatures. The structure is the most important part of the blast furnace body structure.

There are two methods for cooling the blast furnace body: one is to cool the large objects on the furnace wall surface inside the furnace body, and the other is to cool the steel shell outside the furnace body. Conventionally, most furnace walls have been cooled by the cooling surface method. or a staple cooling method.

The former cooling surface method is as shown in Japanese Utility Model Publication No. 52-40164, for example, which uses a flat cooling surface made of copper or prepared alloy as shown in Fig. 1(a), a plan sectional view, and Fig. 1(b), a central vertical sectional view. A large number of bolts are inserted horizontally into the opening of the steel shell with the tips facing into the furnace and tightened with bolts. 3
．． 3' and 6' are constructed, and cooling water is supplied from a water supply port 4.4', circulates through the water channel, and is discharged to the outside of the furnace from a drain port 5.5'. 6.6' is a bolt hole for fixing to the iron shell. For example, the thickness of the cooling box is 80mm. Medium 400, length 1,
The water supply and drainage pipes are connected as a set of 3 to 5 parrots with a size of 1,000 parrots.

The cooling box method generally consists of arranging a large number of shelf-shaped cooling boxes inside the steel shell in a staggered manner, and fixing them horizontally to the steel shell by poles or welding, and surrounding them with refractory bricks for blast furnace walls. This is the cooling structure constructed.

Although this cooling box system has advantages such as the ease of holding the furnace wall bricks and the ability to replace the cooling box when it is damaged, the following drawbacks have been observed in actual practice.

■The cooling effect is limited to the area around the cooling box, and after 5 to 6 years of operation, most of the furnace wall refractory bricks wear out and disappear.Then, the cooling box becomes damaged and the remaining bricks fall off, causing cracks to occur in the steel shell. There is a high risk that operations will become difficult.

■In the later stages of furnace operation, the inner wall of the furnace becomes uneven due to the exposed cooling box before the cooling box is damaged, disturbs the materials being fed, and makes it easier for broken deposits to form, which can lead to poor furnace conditions.

■Once the furnace wall bricks have fallen off, it is completely impossible to repair them during blast furnace operation.

(Φ Countermeasures against gas sol in the furnace body are difficult and there are difficulties in maintaining the airtightness of the furnace.

On the other hand, the latter tape cooling method uses a vertically rectangular cast iron box (stape) as shown in Figure 2. Figure (a) is a front view of the staple as seen from outside the furnace, and (b)
) is the same side view. 7 is a cast-in refractory, 8 is a cast-in pipe for water cooling, and a staple of about 2 m long x 1 m wide is attached to the inside of the steel shell in the height direction of the furnace wall (10) as shown in the figure.
There are several consecutive sets of staples, and the staple in figure (b) corresponds to section A in figure (C).

The water supply is connected vertically through connecting pipes 9, and the cooling water naturally circulates upwards due to the heat load in the furnace, enters the steam-water separation drum 10 at the top stage, and returns to the bottom. Multiple rows of staples are arranged in the circumferential direction of the furnace body.

This method is superior to the cooling box method in terms of uniform cooling of the furnace wall bricks, and has other advantages such as no need for a pot for forced circulation of cooling water, ability to maintain airtightness, and relative ease of use. However, the following drawbacks can be seen in 75X.

■Since the ability to hold large objects on the furnace wall and prevent them from falling off is poor, there are many cases where the refractory bricks fall off and disappear after one or two years of operation, and after that, it becomes difficult to protect the steel shell with bare staples. In two to three years, the staple itself will erode and the iron skin will be exposed, causing cracks and making operation difficult.

(If the cuff cylinder stave is damaged, it is extremely difficult to replace both sides.

■As the temperature of the cooling water increases, the temperature of the refractory lining and the steel skin itself also increases.

■It is extremely difficult to confirm the location of damage.

This invention improves the drawbacks of the conventional cooling structure as described above, and suppresses falling off and chemical corrosion of the refractory by strengthening the support structure of the refractory and increasing the cooling effect. Furthermore, even if the refractory is worn out, it can be easily repaired, and even if the inside of the furnace wall of the cooling structure is damaged, the outer furnace wall cooling zone protects the steel shell, ensuring a stable and long life of the blast furnace wall. The purpose of this project is to provide a cooling structure in which the cooling structure has a one- and two-layer cooling zone structure consisting of an inner cooling zone and a shell side cooling zone. It has a structure in which oblong rectangular cooling plates are connected in the circumferential direction of the furnace body, and these are arranged in multiple stages in the height direction of the furnace wall, and the surroundings are filled with refractories. The shell-side cooling zone is a forced water-cooled cooling tape connected in the height direction of the furnace wall on the outer periphery of the furnace inner cooling zone, that is, near the inside of the furnace wall. A cooling zone with two layers, inside and outside, arranged in multiple rows in the circumferential direction and filled with refractories around them, and connected to a water-cooling pipe that penetrates through the inside of the tape to force water supply and drainage. This is a cooling structure for the blast furnace wall.

Therefore, in order to more effectively achieve the purpose of Jin's invention, the furnace inner cooling zone has a heat absorbing body on the outer surface of the oblong rectangular cooling plate, that is, on the inner surface of the furnace and on the upper and lower surfaces or even on the back surface. One has a structure in which the studs and fins are fixed and the surrounding area is filled with monolithic refractories, and the upper surface of the outer surface of the oblong rectangular cooling plate has plate-shaped ribs that prevent the movement of refractory bricks and have heat absorption functions for cooling. It is desirable to have a structure in which the boards are lined up and fixed along the length of the board, and the surrounding area is constructed with firebrick or monolithic refractory material.

The present invention will be explained below based on drawings showing embodiments. Figs. 6 and 4 show that the structure of the cooling zone inside the furnace includes studs on the inside surface of the furnace of a cooling plate in the form of an oblong rectangular parallelepiped, and fins on the bottom surface. It shows a structure in which the cooling plate is fixed and the area around the cooling plate is filled with monolithic refractory material by pouring or gun spraying.

That is, Fig. 6 is a front view of the vertical cross section taken along the line A-A in Fig. 4 as seen from the inside of the furnace, and Fig. 4 is a longitudinal cross-sectional view taken along line B-B@ in Fig. 6, which is a side view of the furnace wall. be. The left half of the furnace wall in Figure 4 is the furnace inner cooling zone, and the right half is the shell side cooling zone, and the two are integrated.

In both figures, 11 is an oblong rectangular cooling plate, made of cast iron, #
It is a cooling type that is made of steel or cast steel and has a cooling pipe 12 cast inside and forcibly circulates cooling water from the outside using a pressure pump, etc., and the size of one cooling plate is 2,000 width x 2 height.
00 x thickness of approximately 250 am, each cooling plate is located approximately at the center of the thickness of the furnace wall, and is connected horizontally and curved in the circumferential direction of the furnace body to form a ring-shaped connection. Cooling plates are installed at intervals of 400 to 600 u in the height direction. Cooling plate 1
Stans l°15 made of steel or the like are fixed to the outer surface of the inside of the furnace 1 by welding or screwing, for example, at intervals of 50 ffllll in the vertical direction and 2001+111 in the lateral direction. The tip shape is preferably Y-shaped, V-shaped, etc. to facilitate adhesion of the monolithic refractory 14 and at the same time increase the cooling effect as a heat absorber. Numeral fins 15 are welded to the upper and lower surfaces of the cooling plate 11 and have the same function as the studs 16.

The fins 15 can also be provided on the back side of the cooling plate 11.

A shell-side cooling zone is provided on the outer periphery of and in contact with the furnace-side cooling zone constructed as described above. That is, in Fig. 4, reference numeral 16 is a cast iron cooling stave, which has a height of 2,000 width, 1,000 mm thickness, and a depth of about 2501+Il++, and is located at an appropriate distance from the cooling plate 11 and the iron shell 17, and is located between the cooling plate 11 and the iron skin 17. More than ten pieces are connected in the height direction and fixed to the iron shell 17. A water cooling pipe 12' is cast into each cooling stave 16, and the cooling stave 16 is of a forced water cooling type in which cooling water is forcibly circulated using a pressure pump or the like. Such vertical cooling staves are arranged at intervals of, for example, 2.00011111 in the circumferential direction of the furnace body.

Next, in order to construct this cooling zone consisting of two layers inside and outside, first, the cooling stave 16 and the cooling plate 11 are fixed to the steel shell 17 with bolts, nuts, etc., and caster pull monolithic refractories are poured around the cooling stave. After constructing the shell side cooling zone, the surroundings of the cooling plate and the furnace inner wall are divided into horizontal stages as appropriate, and monolithic refractories are sequentially poured or sprayed in contact with the monolithic refractories, thereby forming the lower tier. From then on, the entire periphery of the cooling plate 11 is sequentially filled to construct a cooling zone inside the reactor.

Next, FIGS. 5 and 6 show examples in which the cooling zone inside the furnace is constructed of shaped refractory bricks. FIG. 5 is a partial side view of a furnace wall constructed by replacing the monolithic refractories 14 in the cooling zone inside the furnace in the side view of the furnace wall shown in FIG. 4 with regular bricks 18, and FIG. FIG. 2 is a front view of a vertical cross section taken along the line CC in the figure, viewed from inside the furnace. In both figures, 19 is a rib made of steel plate, which is attached to the cooling plate 1.
For example, on one side of 1, about 200 mm apart (111 of lil11 fire pressure), 240 mm deep (depth of cooling plate),
Iron plates with a height of about 10Qfi (thickness of firebricks) are arranged in parallel and fixed vertically by welding.The ribs 19 are in close contact with both the cooling plate and the firebricks, so they act as heat absorbers to cool the firebricks. At the same time, it has the function of preventing the refractory bricks from moving or falling off. In this case, the area around the cooling stave on the iron shell side can be constructed with four-piece bricks at the same time, or it can be filled with irregularly shaped figures.

When blast furnace operation is performed using the cooling structure of the present invention as described above, first, the refractory 14 or 1B in the inner cooling zone increases the total volume of the cooling disk 11, and also increases the number of The cooling effect due to the heat absorption effect of the studs 1131 and the fins 15 or ribs 19 extends to the entire refractory, and at the same time, the action of holding the refractory is strong, slowing its wear and preventing it from falling off. Therefore, first, the wear rate of the furnace wall is reduced in the cooling zone inside the furnace.

After 6 to 7 years of operation, the refractory inside the furnace gradually wore out and the cooling plate 11
Even if the iron skin is exposed, the cooling zone on the outer side of the iron skin is still intact, so the iron skin will not be heated to a high temperature and it is safe. Furthermore, since the degree and location of damage to the refractory can be confirmed by the temperature rise of the cooling water, the spraying of the refractory inside the furnace can be repaired at an appropriate time. Furthermore, recently, technology has been implemented in which repair monolithic refractories are press-fitted from outside the furnace into the damaged parts of the furnace wall, so it has become possible to hot repair the refractories inside the furnace even during operation.

Therefore, the steel shell side stave 1 in the two-layer cooling zone of this invention
6. Direct contact with the high-temperature contents of the furnace cannot occur.

As explained above, this invention has largely improved the drawbacks of the conventional cooling structure, and while the conventional cooling structure has a furnace wall life of 6 to 7 years, the cooling structure of the present invention can last more than 10 years in the same blast furnace. Its industrial effects are extremely significant, since a long service life can be predicted, and at the same time, situations such as damage to the steel shell can be completely prevented, so stable operation of the blast furnace can be guaranteed for a long period of time.

[Brief explanation of drawings]

Figures 1 and 2 show the cooling structure of a conventional blast furnace body. Figure 2 shows the stave cooling system, (a) is a front view of the stave seen from outside the furnace, (b)
) is a side view, and (c) is an enlarged view of part A in figure. (c) is an overall side view of the stave cooling system. 6 and 4 show an embodiment of the present invention, and FIG. 6 shows a cooling zone inside the furnace, and is a longitudinal sectional front view taken along line A-A in FIG. Figure 4 shows the side view of the furnace wall, and B- in Figure 6.
Bs! FIG. FIG. 5 is a side view of a furnace wall showing another embodiment, and FIG. 6 is a vertical sectional front view taken along the line CC in FIG. 5. 6 to 6, 11...Cooling plate, 12.12'...Cooling pipe, 1
5... Stud, 14... Monolithic refractory, 15.
...Fin, 16...Cooling stave, 17
...Iron skin, 18...Firebrick, 19...Rep. Representative Patent Attorney Sanro Kimura Figure 13 No. 4y! J

Claims (1)

[Scope of Claims] 1. Inside the furnace in which horizontally rectangular parallelepiped cooling plates are connected in the circumferential direction of the furnace body and arranged in multiple stages in the height direction of the furnace body, and the periphery of the cooling plates is filled with refractory material. Cooling zone and 1. A two-layer cooling zone characterized by a forced water cooling type cooling tape installed near the inside of the steel shell on the outer periphery of the furnace inner cooling zone, and the surroundings thereof being filled with refractory material, and a nine steel shell side cooling zone. The cooling structure of the blast furnace wall consists of: 2. A cooling structure for a blast furnace body comprising a two-layer cooling zone as claimed in claim 1, in which a large number of studs and fins are fixed to the outer surface of the cooling disk, and the periphery thereof is filled with a monolithic refractory. 6. From the two-layer cooling zone according to claim 1, in which a large number of plate-like ribs arranged vertically in parallel along the length direction of the upper surface of the cooling plate are fixed, and the cooling plate is surrounded by refractory bricks. The cooling structure of the blast furnace body.